As of now, examples of liquid crystal display devices under development which have wide viewing angle characteristics include liquid crystal display devices utilizing the IPS (In-Plane-Switching) mode or the FFS (Fringe Field Switching) mode, which is a transverse electric field mode, and liquid crystal display devices utilizing the VA (Vertical Alignment) mode.
Examples of the VA mode liquid crystal display devices include MVA (Multidomain Vertical Alignment) mode liquid crystal display devices, in which one pixel includes a plurality of domains of different liquid crystal alignment directions, and CPA (Continuous Pinwheel Alignment) mode liquid crystal display devices in which the liquid crystal alignment direction continuously varies around a rivet or the like formed on an electrode at the center of a pixel.
An example of the MVA mode liquid crystal display device is described in Patent Document 1. In the liquid crystal display device of Patent Document 1, the alignment control means which extend in two mutually-orthogonal directions are provided to form four liquid crystal domains in one pixel, in which the azimuthal angles of the directors representing the liquid crystal domains are 45° relative to the polarization axes (transmission axes) of a pair of polarizing plates in a crossed Nicols arrangement. Assuming that the direction of the polarization axis of one of the polarizing plates is azimuthal angle 0° and that the counterclockwise direction is the positive direction, the azimuthal angles of the directors of the four liquid crystal domains are 45°, 135°, 225°, and 315°. Such a structure which includes four domains in one pixel is referred to as “four-domain alignment structure” or simply “4D structure”.
Another example of the MVA mode liquid crystal display device is described in Patent Document 2. In the liquid crystal display device described in this patent document, the pixel electrode (also referred to as “comb tooth-like pixel electrode” or “fishbone-like pixel electrode”) has a large number of fine slits (narrow cuts) extending in the directions of azimuthal angles 45°, 135°, 225°, and 315°. Liquid crystal is aligned parallel to these slits, whereby the four-domain alignment structure is realized.
A layout example of a gate bus line, a source bus line, and a TFT (Thin Film Transistor) in a liquid crystal display device is described in Patent Document 3.